1. Field of the Invention
This invention relates to novel siliceous compositions prepared by reacting porous silica with aluminum hydride. These compositions are useful as catalysts, particularly as catalysts for acid catalyzed reactions.
2. Background of the Invention
Aluminum hydride has been decomposed to produce aluminum metal coatings on glass objects in U.S. Pat. No. 3,501,333, issued Mar. 17, 1970. These processes are typically low temperature processes, below 250.degree. C. The instant compositions contain no aluminum metal.
U.S. Pat. No. 3,146,209, issued Aug. 25, 1964, teaches a method for producing an aluminum hydride containing silica in which bound water molecules on the silica surface are replaced with aluminum hydride molecules to provide a solid composition basically comprising silica and a hydride source attached thereto. There is no teaching in this reference of any subsequent treatment being applied to their gel material to produce an oxide material comparable to the instant compositions.
U.S. Pat. No. 3,305,590, issued Feb. 21, 1967, discloses a general process for making alumino-silicates. This reference generally teaches impregnation of silica with any decomposable aluminum salt. The aluminum hydride used to prepare the instant composition is not considered a salt but rather is a covalent compound (see Metal Hydrides, Mueller et al, p. 545, Academic Press, 1968).
The compositions of the instant invention have significantly altered catalytic properties over conventional silica supports. Significant improvement in catalyst life is noted. The instant compositions are useful for catalyzing acid catalyzed reaction.